Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for performing offloading procedures for wireless local area network (WLAN)-long term evolution (LTE) integration and interworking in a wireless communication system.
Related Art
The 3GPP LTE is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
Since Rel-8, 3GPP has standardized access network discovery and selection functions (ANDSF), which is for interworking between 3GPP access network and non-3GPP access network (e.g. wireless local area network (WLAN)). The ANDSF may carry detection information of access networks accessible in location of a user equipment (UE) (e.g., WLAN, WiMAX location information, etc.), inter-system mobility policies (ISMP) which is able to reflect operator's policies, and inter-system routing policy (ISRP). Based on the information described above, the UE may determine which Internet protocol (IP) traffic is transmitted through which access network. The ISMP may include network selection rules for the UE to select one active access network connection (e.g., WLAN or 3GPP). The ISRP may include network selection rules for the UE to select one or more potential active access network connection (e.g., both WLAN and 3GPP). The ISRP may include multiple access connectivity (MAPCON), IP flow mobility (IFOM) and non-seamless WLAN offloading. Open mobile alliance (OMA) device management (DM) may be used for dynamic provision between the ANDSF and the UE.
In addition to ANDSF, policy, i.e. radio access network (RAN) rule, has been specified in Rel-12 for interworking between 3GPP access network and non-3GPP access network (e.g. WLAN). By this policy, access network selection and traffic steering between LTE and WLAN can be supported. That is, interworking between LTE and WLAN is moving in the direction of increasingly integrating LTE and WLAN. Accordingly, LTE-WLAN aggregation as well as LTE-WLAN interworking enhancements has been studied recently. But, there has been no agreement how to implement LTE-WLAN aggregation.